I have a very strange problem with my FreeAgent GoFlex 500 GB external HDD, only about the half of it is actually occupied, 200-250 GB, but Windows says no more than 10 GB are available. And so says Linux. But when I checked it with my pal's Mac, it showed the adequate picture, about 50% free disk space.

It all happened last Spring, I got into a really weird situation on-line, I thought my computer was hacked or infected. I was unwise enough to have the external drive connected once in a while when being on the Internet. And at some point I noticed I ran out of space dramatically. I couldn't detect any suspicious / unknown folders. They just all (or some of them) had swollen to about twice its normal size. I tend to think a couple files might have been deleted but the rest appear to be OK.

The disk itself is still 465 GB as it should. I thought about buying another HDD, but I need to figure it all out and find the cause, so it never happens to me again.

Unfortunately, I had very little time trying it on Mac after the accident, it would have been right to check the exact sizes of folders and some files as to compare later.

I deleted some files and noticed that more space was freed. E.g. 5 GB instead of 1.5 GB. But the trick never worked again. So I have to put up with a few GB which is not OK. :smileysad:

The drive has been tested for viruses by numerous antivirus progs, no problem. SeaTools short tests are OK.

Which made me thinking, there might be some opposite to ADS kind of threat when the folder / file size or rather the perception / estimation of it is altered. A mask of sorts or a meta swell which blocks the space and prevents from normal operation.

I have to add that the new folders on that external HDD I currently create, copy or delete, and their content, appear completely normal.

Obviously, I did make copies of anything I personally created. But overall it's about 450 GB which means I'd have to buy yet another external HDD. But the worst is it's 250 GB went 450. So, I'd still have to operate the 'swollen' version on any Windows or Linux based PC. The files do not get smaller when I transfer them to my PC. So ..

I think I may try files vs folders transfering comparison. There may be some difference, who knows. Unfortunately, the major folders are about 100 GB each, and I've run out of space on my machine.

BTW, could you guys enlighten me as to whether Macs are capable of fully fledged operation of Windows formatted HDDs, or it is just about reading?

I wish I had a Mac by my hand to see what's changed. I could try HDD->Mac->PC->newly formatted HDD.

Mine is Seagate FreeAgent GoFlex 500 GB.

I heard Western Digital is either Windows or Mac, and not both. Do I get it right?

When moving files (typically photos) from Macs to Windows/Linux machines, I've noticed duplicate files occationally get created. I'm not sure if this is the Mac creating files for itself and the ones for compatability with other OS's, but it takes up twice as much room as normal.

Have a look to see which files are taking up the space, and if there are duplicate versions of those files around.

"TreeSize Free" should be able to pin down where the space is being used on the device.